Typewriting mechanism for a typewriter machine

ABSTRACT

A typewriting mechanism for a typewriter machine in which mechanism a swingable hammer bracket supporting a typewheel having a number of types formed on the surface of the typewheel, is driven by a single rotary magnet without being disconnected from a type-character selecting mechanism so that the typewheel strikes against the platen and a type-character on the surface of the typewheel is printed on the typewriter paper around the platen. The single rotary magnet also actuates a locking mechanism of the typewheel and a lever for driving an ink ribbon feed mechanism.

Aug. 6, 1974 Decker et a1. 197/55 m of the type- 3,344,378 9/1967Wilhelmson 3,405,794 10/1968 Means..,............... 3,461,996 8/19693,674,126 7/1972 Primary ExaminerRobert E. Pulfrey Assistant ExaminerR.T. Rader Attorney, Agent, or Firm-Maleson, Kimmelman and Ratner [57]ABSTRACT A typewriting mechanism for a typewriter machine in whichmechanism a swingable hammer bracket supporting a typewheel having anumber of types formed on the surface of the typewheel, is driven by asingle rotary magnet without being disconnected from a type-characterselecting mechanism so that the typewheel strikes against the platen anda type-character on the surface of the typewheel is printed on thetypewriter paper around the platen. The single rotary magnet alsoactuates a locking mechanis wheel and a lever for driving an ink ribbonfeed anism.

yoshi all of Japan Communications Tokyo, Japan 197/55, 335/272 B41j l/32197/55, 18, 52, 16; 335/272 TYPEWRITING MECHANISM FOR A TYPEWRITERMACHINE [75] lnventors: Reijiro Kawano; Kazuhiro God both of Kawasaki;Hiroshi Yamakawa, Tokyo; Masa Otsuka, Kawasaki,

Assignee: Kurosawa Tel- Limited,

Filed: May 22,

Appl. No.: 255,697

Field of Search References Cited UNITED STATES PATEN Unite States PatentKawano et al. I

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8 Claims, 23 Drawing Figures Ellner Segawa et a1. 966 BurchfieldPATENTEBMIB m n I 3.827. 543

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RETURN OF FEED PAWL OF THE RIBBON FEED MECHANISM REBBON FEED OPERATIONTYRE CHARACT ER SELECTING PRINTING OPERATION LOCKING OPERATION RELEASEOF LOCKING TIME \PRINTING MOMENT ONE COMPLETE CYCLE OF THE TYPEWR ITI NGORERATI ON TYPEWRITING MECHANISM FOR A TYPEWRITER MACHINE In someconventional typewriting mechanisms of a typewriter machine employing asystem such as a typewheel or type cylinder having types formed on thesurface thereof, directly strikes against the platen, the printingmotion of the typewheel is produced through the operation of camsmounted on a hammer shaft driven through a clutch mechanism and therestoring motion of the typewheel after completion of the printing of atype-character is carried out by a restoring spring, or alternativelythe printing motion is produced by a spring force and the restoringmotion is carried out through the operation of a cam mechanism.

However, these conventional mechanisms are accompanied by such drawbacksthat not only is the top speed of the typewriting operation restrictedbut also, the typewriting mechanism is very complicated and isaccompanied by high production cost and extremely high operation noise.

In some other conventional typewriting mechansisms, the printing motionof the typewheel is produced by an absorption type magnet such as aplunger type magnet.

In this mechanism, there are the advantages that the arrangement of themechanism is relatively simple and control of the hammering action canbe easily carried out. However, there are such serious drawbacks thatthe restoring action of the magnet takes a long time due to its poorstroke to torque characteristics and also, the initial torque of themagnet is very small and as a result, high-speed typewriting operation,now in great demand, can not be achieved.

Furthermore in this mechanism, not only does the change of excitationtime of the magnet produce change of printing pressure but also,simultaneous em ployment of a particular free-flight mechanism isrequired to form a free-flight region in the printing motion of thetypewheel and moreover, impact sound produced by the absorbing motion ofthe plunger magnet, adds undesirable noise to the sound of the printingoperation.

Therefore an object of the present invention is to eliminate theabove-mentioned drawbacks of the conventional typewriting mechanism of atypewriter machine.

Another object of the present invention is to provide a typewritingmechanism for a typewriter machine which can achieve high-speedtypewriting operation.

A further object of the present invention is to provide a typewritingmechanism of a typewriter machine which can reduce operating noise.

Another object of the present invention is to provide a high-speedtypewriting mechanism for a typewriter machine whereby the typewritingoperation sequence including locking operation of the typewheel aftercompletion of a type-character selection, printing operation, and ribbonfeeding operation can be continuously carried out by employing a singledriving source.

A still further object of the present invention is to provide a rotarytype magnet which can be used for said driving source of the typewritingmechanism of a typewriter machine.

The foregoing and other objects, features and advantages of the presentinvention will be apparent from the ensuing description with referenceto the accompanying drawings illustrating a preferred embodiment of thepresent invention wherein:

FIG. 1 is an outside view of the typewriter machine employing a typecarrier provided with the typewriting mechanism of the presentinvention;

FIG. 2 is a plan view of the type carrier provided with the typewritingmechanism of the present invention;

FIGS. 3 and 4 are opposite side views of FIG. 2;

FIG. 5 is a schematically perspective view of the mechanism forselecting a type-character;

FIG. 6 is a schematically perspective view for illustrating themechanism for locking the typewheel;

FIG. 7 is a schematical side view for illustrating the printingoperation of the typewriting mechanism of the present invention;

FIG. 8 is a partial view illustrating the operation of the toggle springemployed in the typewriting mechanism of the present invention;

FIG. 9 is a schematic view illustrating the positional relationshipbetween the rotor and stator of the rotary magnet used in thetypewriting mechanism of the present invention;

FIG. 10 is a diagram showing the torque characteristics curve of therotary magnet according to FIG. 9;

FIG. 11 is a disassembled perspective view of an example of the rotarymagnet;

FIG. 12a, b, c and d are diagrams illustrating the positionalrelationship of the rotor and stator of the rotary magnet and the torquecharacteristic curves;

FIG. 13a and b are diagrams illustrating another positional relationshipof the rotor and stator of the rotary magnet and the torquecharacteristics curve;

FIG. 14a and b are diagrams illustrating still another positionalrelationship of the rotor and stator of the rotary magnet and the torquecharacteristics;

FIG. 15 is a partial plan view illustrating the mechanism for feeding anink ribbon;

FIG. 16 is a partial side view of FIG. 15;

FIG. 17 is a diagram illustrating the operation sequence carried out bythe typewriting mechanism of the present invention.

FIG. 1 is an outside view of a typewriter machine provided with a typecarrier 11 having a typewriting mechanism according to the presentinvention.

The type carrier 11 carries out carriage spacing movement in thedirections shown by the arrow "8 along a conventional platen 13 when thecarrier 11 is required for typewriting operation through an ink ribbon(not shown) on a typewriting paper 15 borne on the platen 13.

Reference numeral 17 shows a keyboard carrying thereon a number of keys,tabulation bar and a space bar, etc.

Reference numeral 19 shows a part of the driving mechanism of the platen13 and other parts.

Referringto FIG. 2 to FIG. 4 illustrating a detailed assembly of thetype carrier 11, there is shown a hammer bracket 21 supporting a typewheel 31, a rotary type hammer magnet 23, a gear box 25, a ribbonfeedmechanism 27 and carrier frames 29a, 29b arranged at the oppositesides of the bracket 21.

The box-like hammer bracket 21 is swingablyassembled to the carrierframe 29a, 29b via pivots 33, and also, the hammer bracket 11 iscombined with a shaft 23a of a hammer magnet'23 by means of a lever arm35 via a locking lever 37 and as a result, according to the rotaryaction of the output shaft 23a of hammer magnet 23 upon being energizedvia an electrical lead 24, the hammer bracket 21 performs the printingoperation as later described in detail. I

At the rear portion of hammer bracket 21, the gear box 25 is arrangedstationary with respect to carrier frames 29a, 29b and through the gearbox 25, shafts 39 and 41 are disposed for selecting a requiredtypecharacter from a number of type-characters formed on the surface ofa typewheel 31, that is, the rotation of respective shafts 39 and 41causes a later described typecharacter selecting operation so that therequired character on the typewheel 31 is located at a selected positionwhere the character can be printed.

At the rear most frames 29a and 29b, a pair of roller members 45, 47 aredisposed so as to be able to slide along a stationary guide rail 49.

Also, at the foremost frames 29a, 29b, a pair of guide bushes 51, 53 aredisposed through which a stationary guide shaft 55 transversely extends.

The guide rail 49 and the guide shaft 55 allow the type carrier 11 toshift in to and fro transverse directions along them.

A spacing belt 57 is fixed to a bracket member 59 rigidly combined withframes 29a, 29b so that the type carrier 11 is shifted to an arbitrarilyselected printing position by shifting forces in the to and frotransverse directions given via the belt 57.

The ribbon feed-mechanism 27 is disposed at an upper portion of frames29a, 29b of type carrier 11 so as to provide a feeding force to carryout the ink ribbon feed operation.

Now the operation of the typewriting mechanism according tothe presentinvention will be described in more detail in accordance with theoperation sequence from the selection of a certain type to thecompletion of the typing of that type.

FIG. schematically illustrates the mechanism for selecting a typecharacter to be printed from a number of type characters arranged on thesurface of typewheel 31 in the vertical and circumferential directions.

A shaft 65 rotatably mounted on hammer bracket 21 via a bearing 66 andsupporting typewheel 31 which is slidably mounted on the shaft 65operates as a type character selection shaft in the circumferentialdirection which may be called circumferential typewheel selection shaft.

Numeral 67 is a rack member having rack gear teeth 69 formed at thefront edge thereof and vertically slidably mounted on hammer bracket 21while being rotatably associated with typewheel 31. This rack member 67operates as a type-character selection element in the verticaldirection.

Numeral 73 is a spiral gear rigidly fixed to the lower portionofcircumferential typewheel selection shaft 65. The elongated shaft 39transmits the action of the circumferential type-character selection tothe typewheel 3 from the outside and also, the elongated shaft 41transmits the other action of the vertical type-character selection tothe typewheel 31 from the outside. Shafts 39 and 41 have rectangularshaped cross-sections. Numeral 75 is a spiral gear housed in the gearbox 25 and rigidly mounted on shaft 39 so that the spiral gear 75together with shaft 39 are capable of sliding in accordance with thecarriage spacing movement of hammer bracket 21. Numeral 77 is a spurgear fixedly mounted on shaft 41 so that spur gear 77 together withshaft 41 are capable of sliding also in accordance with the carriagespacing movement of hammer bracket 21. Numeral 79 is an idler gearconcentrically and rotatably mounted on a flange (not shown) of spiralgear 75 while being in a meshing engagement with spur gear 77 and rackgear teeth 69 of rack member 69. That is gear 79 receives its drivingforce from gear 77.

As will be understood from the foregoing and later description, hammerbracket 21 is capable of swinging about pivots 33 with respect tocarrier frames 29a and 29b (not shown) so as to carry out the printingoperation. A line A-A passing through the center of pivots 33 in theaxis of the above-mentioned swinging movement of hammer bracket 21.

According to one of features of the present invention, spiral gear 75and idler gear 79 keep a meshing engagement with spiral gear 73 and rackgear teeth 69 of rack member 67 respectively on the line A-A'. In otherwords, the respective meshing points always lie on the line A-A' aboutwhich hammer bracket 21 swings to carry out the printing action.

In this case, a suitable amount of backlash may be provided at therespective meshing points so that interference between respective gearsmay be avoided when hammer bracket 21 starts to swing for carrying outthe printing action.

In the above arrangement of a type-character selection mechanism, when asignal which commands the selection of a certain typecharacter, is givento both shafts 39 and 41, both shafts 39 and 41 rotate to thepreselected amount of rotation required for selecting the certaintype-character on typewheel 31 and the rotational movement of shaft 39is transmitted to shaft 65 through the meshing engagement of spiralgears 75 and 73 so as to effectuate the circumferential typewheelselection while the rotational movement of shaft 41 is simultaneouslytransmitted to rack member 65 through the meshing engagement of gears 77and 79 and rack gear teeth 69 so as to effectuate the vertical typewheelselection. That is to say, typewheel 31 is positioned to a predeterminedprinting position where a selected type on the surface thereof can beprinted on a typewriter paper (not shown) upon swinging of hammerbracket 21 about pivots 33.

According to the above arrangement wherein the meshing points of thegears for transmitting the typecharacter selecting action alwayscorrectly lie on the axis about which hammer bracket 21 swings to carryout the printing action, it is not necessary to disengage thetype-character selecting mechanism from hammer bracket 21 supportingtypewheel 31 every time hammer bracket 21 carries out the printingaction so that the printing action of hammer bracket 21 can becontinuously carried out after completion of the typecharacter selectingoperation without any interruption and this fact results in thehigh-speed typewriting operation capability of the typewriting mechanismof the present invention.

Now referring to FIG. 6, a mechanism for locking typewheel 31 aftercompletion of the circumferential and the vertical type-characterselection, is schematically and perspectively shown.

As is seen from FIG. 3, thislocking mechanism is arranged at the lowerportion of swingable hammer bracket 21 of the type carrier 11.

In FIG. 6, immediately before completion of the type-character selectingoperation, hammer magnet 23 is energized to rotate output shaft 23a inthe clockwise direction against the force of a spring 103 and as aresult locking lever 37 starts to rotate in the counterclockwisedirection about shaft 370 and against the force of a spring 105 vialever arm 35 and engages with a notch 85a of a trigger lever 85 at itsone end 37b. And at this moment, the other end 370 of locking lever 37is disconnected from an engagement with a vertical locking lever 87 anda rotational locking lever 89 so that bothlocking levers 87' and 89 arerotated about a vertical shaft 91 in the clockwise direction due to theforces of respective springs 93- and 95.

As a result of this, locking levers 87 and 85 simultaneously engage withone of the locking grooves 97 formed at the rear edge of rack member 67and one of the locking teeth 101 of a locking wheel 99 fixed at thelower end of shaft 65 of typewheel 31 respectively as shown in FIG. 6,and typewheel 31 is then put into a locked state so that a certainselected type thereon can be correctly printed by the swinging movementthereof.

It should be understood from FIG. 6 that at the moment when thetypewriting operation is completed and hammer magnet 23 is-deenergized,the forces of the springs 103 and 105 cause locking lever 37 to rotatein the clockwise direction so that the end 370 of locking lever 37returns to re-engage with both vertical and ro- -tational locking levers87 and 89 while causing a coun- 31 while referring to FIG..7, energizedhammer magnet 23 continues to pull locking lever 37 via lever arm 35againstsprings 103 and 105 until the end 37b of locking lever 37contacts the upper edge of notch 85a of trigger lever 85 and thecounterclockwise rotation of locking lever 37 is restricted momentarilyby trigger lever 85.

However, further pulling force of hammer magnet 23 applied to lockinglever 37 via lever arm 35 causes hammer bracket 21 to start its swingingaction about pivots 33 fixed to carrier frames 29a, 29b (not shown inFIG. 7) from an initial position away from platen 13 (not shown in FIG.7).

As soon as the swinging action of hammer bracket 21 starts, hammermagnet 23 is deenergized, and there fore, the torque thereof applied tooutput shaft 23a is reduced. However, at this moment due to the inertiaof swinging hammer bracket 21, the printing operation of hammer bracket21 is positively achieved, that is to say, typewheel 31 strikes againstthe typewriter paper 15 around platen 13 through the ink ribbon similarto the conventional manner so that the selected type-chamber is printedon the. paper 15.

When typewheel 31 strikes against platen 13 through paper 15, suddenstoppage of the swinging action of hammer bracket 21 produces inertialrotation of output shaft 23a which maintains locking lever 37 in thepulled state by lever arm 35 and as a result, locking of typewheel 31 iskept during the printing action of hammer bracket 21.

When the inertial rotation of output shaft 23a of hammer magnet 23 isexhausted, the forces of springs 103 and act to release the locking oftypewheel 31 as previously explained and simultaneously, act to bringback hammer bracket 21 to the initial position where hammer bracket 21contacts a stopper 107 fixedly attached to the inner side of carrierframe 29a as shown in FIG. 4.

Thus, the printing operation of hammer bracket 21 is completed.

Here it should be noted in FIGS. 3 and 8 that a toggle spring 109bridged between carrier frame 29a and hammer bracket 21 has its neutralpoint at the preselected position which is five-sixths the distance fromthe initial position of hammer bracket 21 to platen 13.

Therefore, when hammer bracket 21 is swung exceeding the neutralposition, toggle spring 109 forces hammer bracket 21 to further swingtoward platen 13, and until hammer bracket 21 reaches the neutralposition, toggle spring 109 applies the spring force to hammer bracket21 so as to restrict the swinging action of hammer bracket 21. That isto say, toggle spring 109 always resists the occurrence of both swingingand returning actions of hammer bracket 21, so that both locking andrelease of locking of typewheel 31 are accomplished before theoccurrence of movement of hammer bracket 21.

Now, a brief description of the rotary type hammer magnet 23 will begiven with reference to FIG. 9 and FIG. 10.

FIG. 9 illustrates the positional relationship between the stator andthe rotor of the rotary magnet 23.

In the structure of hammer magnet 23, a rotor fixedly mounted on outputshaft 23a (FIG. 6) and having equi-angularly spaced poles 117 rotateswith respect to a stationary stator 119 which has poles arranged at thesame pitch as poles 117 of rotor 115.

In the non-operating state, poles 117 of rotor 115 are positioned so asto be staggered from poles 121 of stator 119 by an angle 6, as shown inFIG. 9(a,).

In this state, when stator 1 19 is energized, the attractive forceacting between stator 119 and rotor 115 produces maximum torque whichmakes rotor 115 rotate with output shaft 23a, and when rotor 115 rotatesuntil poles 117 are aligned with poles 121 of stator 119 (position 0,,of FIG. 9(a refers to), the torque of output shafts 23a or rotor 115 isextinguished.

FIG. 10 indicates the torque characteristics curve of rotary hammermagnet 23 with respect to the difference of angle of stagger betweenrotor 115 and stator 119.

In the case where this hammer magnet 23 is employed for driving thetypewriter mechanism of the present invention, the arrangement is suchthat at an angular position 1 of FIG. 10, the printing action oftypewheel 31 starts, and at an angular position 0,, of FIG. 10, theprinting of a type is completed.

In FIG. 10, a dotted line indicates a torque characteristics curve ofspring 103 which resists the rotation of rotor 115 and output shaft 23a.

According to the foregoing, it will be understood that at the initialstate of printing action of typewheel 31, hammer magnet 23 applies alarge torque to typewheel 31 so as to effectively accelerate theswinging action of typewheel 31, but according to the progress of theswinging action of typewheel 31, the torque of hammer magnet 23 becomessmall while the torque of the resisting spring 103 becomes large and asa result, the printing action of typewheel 31 is carried out merely byits inertial swinging action so that printing of a type is performed bya momentary contact only of typewheel 31 with platen 13. Therefore,clear and uniform printing of a type can be achieved because novibrating action of typewheel 31 occurs due to the small contactpressure between typewheel 31 and platen 13. That is to say, doubleprinting action of typewheel 31 can be completely avoided.

Also, it will be understood that by controlling the exciting currentgiven to hammer magnet 23, control of the printing torque. applied totypewheel 31 is easily carried out. I I

Therefore, corresponding to the number of typewriter papers which mustbe printed at the same time, the above contact pressure betweentypewheel 31 and platen 13 can be suitably and easily controlled.

Further, it will be understood that according to the employment ofrotary hammer magnet 23, impact occurs only when typewheel 31 strikesagainst platen l3 and also, when hammer bracket 21 returns to stopper107 (FIG. 4) and as a result, noise of the typewriting mechanism isextremely reduced compared with the conventional mechanism wherein heavyhammering action is used for producing printing pressure.

Further, it will be understood from FIG. that as the torque of hammermagnet 23 is almost zero, return of typewheel 31 due to the torque ofspring 103 starts immediately after completion of printing of a type sothat the whole typewriting operation can be carried out at high-speed.

Now, further detailed description with respect to the rotary type hammermagnet will be hereinafter mentioned referring to an example thereofshown in FIG. 11 toFIG. 14. t

InFIG. l1,shaft 23a ismade of magnetic material, and rotors 115a, 115bhaving a plurality of poles 117a, 117b, are fixedly mounted on shaft23a. Numeral 123 is a bobbin made of non-magnetic material and isarranged on shaft 23a and between rotors 115a, 115b while keepingsuitable gaps between bobbin 123 and these other elements. .Numeral 127is an excitation winding installed on the bobbin 123. Numerals 119a, 11%are stators inserted over rotors 115a, 115b, and excitation windings 127while keeping slight radial air gaps therebetween. These stators 119a,11% are provided with poles 121a, 12lb arranged at the same equiangularspaces as rotor-poles 117a, 117b. Numerals 129a, 12% are bearingssupporting the opposite ends of shaft23a so that shaft 23a can berotated. Numerals 131a, 131b are bracket members for stationarilysupporting the above-mentioned stators 119a, 11% as well as holdingbearings 129a, 12% as shown in FIG. 11.

Numeral 125 is a pawl provided for the abovementioned bobbin 123 forrestricting the rotation of bobbin 123.

In the above arrangement of the hammer magnet 23, when excitationcurrent is applied to excitation windings 127, magnetic flux throughshaft 23a, rotors 115a,

b and stators 119a, 11% is formed and as a result, magnetic attractiveforces are produced between poles 117a and 121a, and between poles 1l7band 121b, re spectively.

These attractive forces produce a torque on rotors 115a, 115b and shaft23a when poles of rotors 115a, 115b and poles of stators 119a, 11% arein a staggered relationship and as a result, shaft 23 rotates until therotors and stators are aligned.

When the excitation is stopped, shaft 23a with rotors 115a, 115b iscapable of returning to the initial state by a suitable means such as aspring.

Now, assuming that in the non-operating initial state, poles of rotors115a, 115b are positioned between poles of stators 119a, 11% as shown inFIG. 12c, and in the operating state, poles of rotors 115a, 115b aremagnetically attracted to poles of stators 119a, 1 19b as shown in FIG.12a, the torque characteristics curve shown in FIG. 12d is obtainedcorresponding to angle of stagger between poles of rotors 115a, 115b andstators 119a, 11% in both angular directions as shown by angles 0 and -0in FIG. 12a.

In FIG. 12d, 6 and 6, indicate positions where the maximum torque isobtained from rotors 115a, 115b.

' FIG. 120 indicates the positional relationship between rotors 115a,115b and stators 119a, 11% when this maximum torque is obtained.

As is seen from FIG. 120, the maximum torque can be obtained when poles117a, 117b of rotors 115a, 115b depart from poles 121a, l21b of stators119a, 11%.

The positions 6 and 6 of FIG. 12d indicate the second zero torquepositions where poles 1170, 117b of rotors 115a, 115b are positioned inthe middle of poles 121a, 121b of stators 119a, 11% as is seen from FIG.12c.

In the torque characteristics shown in FIG. 12d, if the region 6, onlyfrom the position 6 is used, the initial torque becomes maximum whilethe end torque becomes minimum.

Therefore, the initial maximum torque serves as an acceleration torquefor shaft 23a and the end minimum torque serves to restrict theimpacting action of shaft 23a.

Referring to FIG. 13a, b, another positional relationship between therotors and stators of hammer magnet 23 and its torque characteristicscurve are indicated.

In FIG. 13a, an example wherein stators 119a and 11% are staggered fromeach other by an angle 0,, is shown and in this case, the maximum torqueobtained from shaft 23a may be reduced in value. However, an averagedtorque characteristics curve can be obtained as shown in FIG. 13b. Andit will be understood that if 0,, is suitably changed, any kind oftorque characteristics curve can be obtained.

FIG. 14a, b indicates another case in which output shaft 23a of hammermagnet 23 has a large end torque, because the rotation of output shaft23a is stopped by a suitable magnetic stop member provided over aportion of the respective poles of rotor 115a or 11512. That is to say,when the motion of shaft 23a is stopped by the stop member, magneticattractive forces between rotors 115a, 115b and stators 119a, 1191;produce the largest or maximum torque as shown in FIG. 14b.

In this case, the magnitude of the end torque can be suitably set bychanging the number of stop members which may be provided for all poles117a, 1l7b of rotors 1 15a, 1 15b or for merely selected numbers ofpoles 117a; ll7b of rotors 115a, 115b.

Of course, the stop members may be provided for poles 121a, 121b of thestators instead whereby the same effect as the foregoing can beexpected.

- Further, in the above arrangement of the rotary type magnet, slidingsurfaces exist only in bearings 129a, 12% and as a result, the abrasioneffect which exists in the conventional plunger type magnet, can begreatly reduced or eliminated.

Also, almost all elements such as rotors 115a, 115b, stators 119a, 119b,and a shaft 23a, are made of magnetic material, so that the leakage ofmagnetic flux produced by energizing of excitation windings 127 is verysmall and as a result, a magnetic driving source of superior efficiencycan be obtained.

Now, the typewriting mechanism of the present invention will be againconsidered.

FIGS. 15 and 16 illustrate a mechanism for. feeding In the abovemechanism, the ribbon feed operation is carried out when hammer bracket21 swings back to the initial position.

When hammer bracket 21 swings toward platen 13 to carry out a printingoperation, feed pawl 153 of the ribbon feed mechanism 27 returns to itsinitial position.

FIG. 17 is a diagram schematically illustrating the operational sequenceof the typewriting mechanism of the present invention, and the abscissaindicates time (T), and the ordinate indicates progress of therespective operations.

In the diagram of FIG. 1, period T, represents one complete cycle of thetypewriting operation from the type-character selection to the releaseof locking of the typewheel. In the period T firstly, the type-characterselecting operation is carried out and then, immediately beforecompletion of the type-characterselecan ink ribbon for-the next:typewriting operation after completion of printing of a certain type.

This mechanism is actuated by the swinging action of hammer bracket 21.

In FIGS. 15 and 16, when hammer bracket 21 carries out swinging actionas described before, a feed arm 141 engaged with a pin 143 fixed tohammer bracket 21 is actuated to carry out a swinging action about anaxis 145, and this swinging action of feed arm 141 is transmitted to theribbon feed mechanism 27 via a feed link Feed link 141 is connected tothe middle portion of a feed lever 149 which is rotatable about avertical axis 151 disposed at one end of feed lever 149, and therefore,movement of feed link 147 in the direction shown by an arrow .Pcausesthe swinging motion of feed ratchet wheel 155a through engagement of astop pawl 157a and ratchet of ratchet wheel 155a as can be seen fromFIG. 15.

A spring 159 provides a spring force to effectuate positive engagementof feed pawl 153 and ratchet wheel 155a and also, of back stop lever 157and ratchet wheel 155a.

The rotation of ratchet wheel 155a provides the ribbon feeding operationthrough spool 161a because a ribbon cartridge (not shown) which containsan ink ribbon, is mounted on both spools 161a, 161b.

That is, when one of the spools 161a, 161b rotates, the winding actionof an ink ribbon is carried outwithin the cartridge.

When the ribbon feed operation caused by ratchet wheel 155a iscompleted, feed pawl 153 engages with ratchet-wheel l55b through areversing mechanism (not-shown) and the ribbon feed operation caused by6 ratchet wheel 155b is carried out in the reverse direction of theforegoing.

tion, the locking operation of the typewheel starts and when the lockingoperation is completed, the printing operation starts and the printingof a type is completed at time T After completion of the printingoperation, the ribbon feeding operation and the releasing operation oflocking of the typewheel are carried out.

It will be understood from the foregoing and the diagram of FIG. 17 thatas the locking of the typewheel is released immediately after completionof the printing operation, the next typewriting operation can startimmediately and as a result, high-speed typewriting can be achievedaccording to the present invention.

Now it is to be understood that numerous variants and modifications ofthe typewriting mechanism of the typewriter machine can be effectuatedwithin the scope and the spirit of the present invention.

What is claimed is:

l. A typewriting mechanism for a typewriter machine comprising bracketmeans capable of swinging about an axis toward the platen of thetypewriter machine, a typewheel having a number of types on the surfacethereof and rotatably and vertically movably supported by said bracketmeans,

said typewheel being capable of selecting one of said types through atype-character selecting mechanism having a gear meshing engagement,rotary magnet means combined with said bracket means and actuating theswinging motion of said bracket means upon being electrically energizedso that said typewheel strikes against said platen while carrying outprinting of a type of said typewheel,

rotary magnet means comprising a rotatable shaft,

rotor poles which are fixedly mounted on and equiangularly arrangedaround said rotatable shaft, stator poles equiangularly arranged aroundsaid rotor poles, and excitation windings provided for excitation ofsaid stator poles and said rotor poles, and rotor poles, and

spring means for maintaining an initial position of said bracket means,said initial position of said bracket means being defined by a fixedlyarranged stopper with which said bracket means comes into contact by theforce of said spring means,

said rotary magnet means being associated with said bracket means in amanner so that when said bracket means stays in the initial positionsaid rotor poles are positioned so as to be angularly staggered fromsaid stator poles.

2. A typewriting mechanism for a typewriter machine as claimed in claim1, wherein the center of swing of said bracket means and the points ofcontact of the pitch circles of respective meshed gears of saidtypecharacter selecting mechanism lie on the same line.

3. A typewriting mechanism for a typewriter machine as claimed in claim1, further comprising link means driven by said rotary magnet meanscombined with said bracket means, said link means locking the rotationaland vertical motion of said typewheel with respect to said bracket meanswhereby said selected type is positioned to be printed.

4. A typewriting mechanism for a typewriter machine as claimedin claim1, further comprising lever means actuated by said bracket means throughsaid swinging motion of said bracket means, said lever means including afeed pawl for driving an ink ribbon feed mechanism, said feed pawlengaging said feed mechanism to feed said ink ribbon when said bracketmeans swings back to an initial position and said feed pawl returning toits initial position when said bracket means swings so that saidtypewheel strikes against said platen.

5. A typewriting mechanism for a typewriter machine as claimed in claim1, wherein said bracket means and said rotary magnet means are combinedinto carriage means which carries out carriage spacing motion along saidplaten during the typewriting operation.

6. A typewriting mechanism for a typewriter machine comprising:

bracket means capable of swinging about an axis toward the platen of thetypewriter machine;

a typewheel having a number of types on the surface thereof androtatably and vertically movably supported by a vertical shaft mountedon said bracket means;

type-character selecting means including gear meshing engagement forcarrying out selection of one of said types of which is to be printed;

a rotary magnet having an output shaft rotated upon electricalenergization of the rotary magnet;

means for actuating a swinging motion of said bracket means uponrotation of the output shaft of said'rotary magnet so that saidtypewheel strikes against said platen while carrying out printing of atype of said typewheel, said actuating means comprising a first leverarm radially extending from said output shaft of said rotary magnet, asecond lever arm having one end connected to the outermost end of saidfirst lever arm and the other end associated with bracket means, andspring means for exerting restoring force on said second lever arm,

said rotary magnet and said bracket means being incorporated into acarriage means carrying out spacing motion along said platen during thetypewriting operation; v

said rotary magnet comprising rotor poles which are fixedly mounted onand equiangularly arranged around said output shaft, stator polesequiangularly arranged around said rotor poles, and excitation windingsprovided for excitation of said stator poles and said rotor poles; and

said spring means for maintaining an initial position of the bracketmeans, said initial position of said bracket means being defined by afixedly arranged stopper with which the bracket means comes into contactby the force of the spring means;

said rotary magnet being associated with said bracket means in a mannerso that when the bracket means stays in the initial position said rotorpoles are positioned so as to be angularly staggered from said statorpoles.

7. A typewriting mechanism for a typewriter machine as claimed in claim6, wherein said type-character selecting means comprises:

a first rectangular traverse shaft rotated to transmit a circumferentialtype-character selecting motion to said typewheel;

a second rectangular transverse shaft rotated to transmit a verticaltype-character selecting motion to said typewheel;

a first gear fixedly mounted on said first transverse shaft transverselysliding in accordance with said spacing movement of said bracket means;

a second gear fixedly mounted on said second transverse shafttransversely sliding in accordance with the spacing movement of saidbracket means;

an idler gear freely rotatable on said first rectangular transverseshaft and being in meshing engagement with said second gear;

a third gear fixedly mounted on said vertical shaft and engaging withsaid first gear to cause said circumferential type-character selectingmotion of said typewheel via said vertical shaft upon rotation of saidfirst shaft;

a rack member having gear teeth formed at one vertical edge thereof andvertically slidably mounted on said bracket means while being rotatablyassociated with said typewheel, said rack gear teeth being in meshingengagement with said idler gear to cause said vertical type-characterselecting motion of said typewheel upon rotation of said second shaft,and;

the points of contact of the pitch circles of said first and third gearsand of said idler and rack gears lie on the center line of swingingmotion of said bracket means.

8. A typewriting mechanism for a typewriter machine as claimed in claim6, further comprising locking means for releasably locking saidtypewheel upon printing of said type to be printed comprising:

a member having vertically arranged teeth defining locking groovesbetween said adjacent teeth and vertically slidably mounted on saidbracket means while being rotatably associated with said typewheel;

a locking gear fixed on said vertical shaft;

a first horizontal locking lever angularly movable on said bracket meansand being engageable with one of said locking grooves of said member inan operated position thereof;

a second horizontal lever angularly movable on said bracket means andbeing engageable with said locking gear in an operated position thereof;

spring means for urging said first and second horizontal locking leversto initial positions thereof, and;

a third locking lever associated with said second lever arm to urge saidfirst and second locking levers to the operated position from theinitial positions in accordance with said electrical energization ofsaid rotary magnet.

1. A typewriting mechanism for a typewriter machine comprising bracketmeans capable of swinging about an axis toward the platen of thetypewriter machine, a typewheel having a number of types on the surfacethereof and rotatably and vertically movably supported by said bracketmeans, said typewheel being capable of selecting one of said typesthrough a type-character selecting mechanism having a gear meshingengagement, rotary magnet means combined with said bracket means andactuating the swinging motion of said bracket means upon beingelectrically energized so that said typewheel strikes against saidplaten while carrying out printing of a type of said typewheel, rotarymagnet means comprising a rotatable shaft, rotor poles which are fixedlymounted on and equiangularly arranged around said rotatable shaft,stator poles equiangularly arranged around said rotor poles, andexcitation windings provided for excitation of said stator poles andsaid rotor poles, and rotor poles, and spring means for maintaining aninitial position of said bracket means, said initial position of saidbracket means being defined by a fixedly arranged stopper with whichsaid bracket means comes into contact by the force of said spring means,said rotary magnet means being associated with said bracket means in amanner so that when said bracket means stays in the initial positionsaid rotor poles are positioned so as to be angularly staggered fromsaid stator poles.
 2. A typewriting mechanism for a typewriter machineas claimed in claim 1, wherein the center of swing of said bracket meansand the points of contact of the pitch circles of respective meshedgears of said type-character selecting mechanism lie on the same line.3. A typewriting mechanism for a typewriter machine as claimed in claim1, further comprising link means driven by said rotary magnet meanscombined with said bracket means, said link means locking the rotationaland vertical motion of said typewheel with respect to said bracket meanswhereby said selected type is positioned To be printed.
 4. A typewritingmechanism for a typewriter machine as claimed in claim 1, furthercomprising lever means actuated by said bracket means through saidswinging motion of said bracket means, said lever means including a feedpawl for driving an ink ribbon feed mechanism, said feed pawl engagingsaid feed mechanism to feed said ink ribbon when said bracket meansswings back to an initial position and said feed pawl returning to itsinitial position when said bracket means swings so that said type wheelstrikes against said platen.
 5. A typewriting mechanism for a typewritermachine as claimed in claim 1, wherein said bracket means and saidrotary magnet means are combined into carriage means which carries outcarriage spacing motion along said platen during the typewritingoperation.
 6. A typewriting mechanism for a typewriter machinecomprising: bracket means capable of swinging about an axis toward theplaten of the typewriter machine; a typewheel having a number of typeson the surface thereof and rotatably and vertically movably supported bya vertical shaft mounted on said bracket means; type-character selectingmeans including gear meshing engagement for carrying out selection ofone of said types of which is to be printed; a rotary magnet having anoutput shaft rotated upon electrical energization of the rotary magnet;means for actuating a swinging motion of said bracket means uponrotation of the output shaft of said rotary magnet so that saidtypewheel strikes against said platen while carrying out printing of atype of said typewheel, said actuating means comprising a first leverarm radially extending from said output shaft of said rotary magnet, asecond lever arm having one end connected to the outermost end of saidfirst lever arm and the other end associated with bracket means, andspring means for exerting restoring force on said second lever arm, saidrotary magnet and said bracket means being incorporated into a carriagemeans carrying out spacing motion along said platen during thetypewriting operation; said rotary magnet comprising rotor poles whichare fixedly mounted on and equiangularly arranged around said outputshaft, stator poles equiangularly arranged around said rotor poles, andexcitation windings provided for excitation of said stator poles andsaid rotor poles; and said spring means for maintaining an initialposition of the bracket means, said initial position of said bracketmeans being defined by a fixedly arranged stopper with which the bracketmeans comes into contact by the force of the spring means; said rotarymagnet being associated with said bracket means in a manner so that whenthe bracket means stays in the initial position said rotor poles arepositioned so as to be angularly staggered from said stator poles.
 7. Atypewriting mechanism for a typewriter machine as claimed in claim 6,wherein said type-character selecting means comprises: a firstrectangular traverse shaft rotated to transmit a circumferentialtype-character selecting motion to said typewheel; a second rectangulartransverse shaft rotated to transmit a vertical type-character selectingmotion to said typewheel; a first gear fixedly mounted on said firsttransverse shaft transversely sliding in accordance with said spacingmovement of said bracket means; a second gear fixedly mounted on saidsecond transverse shaft transversely sliding in accordance with thespacing movement of said bracket means; an idler gear freely rotatableon said first rectangular transverse shaft and being in meshingengagement with said second gear; a third gear fixedly mounted on saidvertical shaft and engaging with said first gear to cause saidcircumferential type-character selecting motion of said typewheel viasaid vertical shaft upon rotation of said first shaft; a rack memberhaving gear teeth formed at one vertical edge thereof and verticallyslidably mounted on said bracKet means while being rotatably associatedwith said typewheel, said rack gear teeth being in meshing engagementwith said idler gear to cause said vertical type-character selectingmotion of said typewheel upon rotation of said second shaft, and; thepoints of contact of the pitch circles of said first and third gears andof said idler and rack gears lie on the center line of swinging motionof said bracket means.
 8. A typewriting mechanism for a typewritermachine as claimed in claim 6, further comprising locking means forreleasably locking said typewheel upon printing of said type to beprinted comprising: a member having vertically arranged teeth defininglocking grooves between said adjacent teeth and vertically slidablymounted on said bracket means while being rotatably associated with saidtypewheel; a locking gear fixed on said vertical shaft; a firsthorizontal locking lever angularly movable on said bracket means andbeing engageable with one of said locking grooves of said member in anoperated position thereof; a second horizontal lever angularly movableon said bracket means and being engageable with said locking gear in anoperated position thereof; spring means for urging said first and secondhorizontal locking levers to initial positions thereof, and; a thirdlocking lever associated with said second lever arm to urge said firstand second locking levers to the operated position from the initialpositions in accordance with said electrical energization of said rotarymagnet.